In fact, local troopers say the number of overall DUI's is down compared to this time last year.
Officials say they wouldn't be surprised by a rise in DUI's down the road.
Speeding, swerving and delayed traffic responses can be a sign someone's toking up. Once they've pulled them over, troopers can better judge their possible intoxication.
"Pulse rates high, pupils are dilated. They're just slow and lethargic - their distance and time perception is just off," said Washington State Patrol Sergeant Brian Mihelich.
A DUI is a gross misdemeanor.